# Metafor

ULiege - Aerospace & Mechanical Engineering

## Materials

Since radiation interactions are boundary conditions interactions (LoadingInteraction), no materials must be associated to the element.

## Element

Therefore, the first step consist in defining an ElementProperties, as

prp = ElementProperties(typeEl)
prp.put(param1, value1)
prp.depend(param1, fct1, Lock1)) #optional
...

where

 typeEl desired element (for example Tm[2]Rayonnement[2|3]DElement) param1 name of the property associated to the element (for example RAY_EMISSIVITY value1 value of the corresponding property fct1 function which characterizes the dependency of the property (optional: no fct if no dependency) Lock1 Lock which defines the dependency variable of the property (compulsory if there is a dependency)

### Tm[2]Rayonnement[2|3]DElement

Using radiation elements requires the use of Kelvin in the entire model !!!

Thermal radiation element with given room temperature. First or second degree.

TODO : Ajouter équations de rayonnement

#### Parameters

Name Description Dependency
STIFFMETHOD Method used to compute the stiffness matrix\\= STIFF_ANALYTIC : analytic matrix (default)
= STIFF_NUMERIC : numerical matrix
-
BOLTZMANN_CST Boltzmann Constant (required to set units)
= $5.67e^{-8} W/m^2K^4$
= $5.67e^{-11} mW/mm^2K^4$
Set
RAY_EMISSIVITY Relative emissivity between two gray bodies (solid / room)
$\epsilon = \frac{\epsilon_1 * \epsilon_2}{\epsilon_1 + \epsilon_2 - \epsilon_1 * \epsilon_2}$
time
RAY_TEMP_AMB Room temperature (K) time
NPG Number of integration points (default : tm : 2 / tm2 : 3) -

## Interaction

The interaction is defined as:

load = LoadingInteraction(no)
interactionset.add(load)
 no number of the Interaction gObject1, gObject2 mesh geometric entity where the boundary conditions are applied prp Properties of boundary condition elements to generate